DOI QR코드

DOI QR Code

Changes in the Specific Gravity of Pacific Cod Gadus macrocephalus, During the Early Life Stages

대구(Gadus macrocephalus)의 초기 발생시기의 비중변화

  • Lee, Hwa Hyun (Institute of Geomatics, Pukyong National University)
  • 이화현 (부경대학교 지오메틱연구소)
  • Received : 2018.06.04
  • Accepted : 2018.06.22
  • Published : 2018.06.30

Abstract

The Pacific cod Gadus macrocepahlus, lays demersal eggs and the hatching larvae rise toward the surface layer of the ocean to feed. The change in the specific gravity of eggs and larvae was investigated to examine their vertical distribution and movement in the water column. The specific gravities of fertilized eggs and various size classes of larvae were measured using a density gradient apparatus. In total, the instantaneous specific gravity of 146 eggs and 225 larvae were measured. To prevent any disturbance in the gradient water column due to larval movement, 0.004% MS222 was used for anesthesia. Due to their high specific gravity, eggs spawned were deposited over the sea-bed of the spawning ground. The specific gravity of hatching larvae decreased abruptly. However, Pacific cod larvae still had a comparatively high specific gravity at hatching ($1.03655{\pm}0.00146g/cm3$, n=4, mean SL=3.62 mm) and their specific gravities tended to decrease as they grew. The specific gravity stabilized 6 days after hatching ($1.02590{\pm}0.00212g/cm3$, n=15, mean SL=4.67 mm) and the cod larvae were eventually able to float in the water column.

Keywords

References

  1. Bian X, Zhang X, Sakurai Y, Jin X, Gao T, Wan R and Yamamoto J. 2014. Envelope surface ultrastructure and specific gravity of artificially fertilized Pacific cod Gadus macrocephaluseggs. J Fish Biol 84, 403-421. https://doi.org/10.1111/jfb.12292.
  2. Chyung MK. 1977. The fishes of Korea. Il Ji Sa Publishing Co., Seoul, Korea,
  3. Coombs SH. 1981. A density-gradient column for determining the specific gravity of fish eggs, with particular reference to eggs of the mackerel Scomber scombrus. Mar Biol 63,101-106. https://doi.org/10.1007/BF00394667.
  4. Coombs SH, Boyra G, Rueda LD, Uriarte A, Santos M, Conway DVP and Halliday NC. 2004. Buoyancy measurements and vertical distribution of eggs of sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus). Mar Biol 145, 959-970. https://doi.org/10.1007/s00227-004-1389-4.
  5. Goarant A, Petitgas P and Bourriau P. 2007. Anchovy (Engraulis encrasicolus) egg density measurements in the Bay of Biscay: evidence for the spatial variation in egg density with sea surface salinity. Mar Biol 151, 1907. https://doi.org/10.1007/s00227-007-0624-1.
  6. Hart JL and Clemens WA. 1973. Pacific fishes of Canada (Bulletin 180). Fisheries Research Board of Canada, Ottawa. Canada.
  7. Hurst TP, DW Cooper, JS Scheingross, EM Seale, BJ Laurel and ML Spencer. 2009. Effects of ontogeny, temperature, and light on vertical movements of larval Pacific cod (Gadus macrocephalus). Fish Oceanogr 18, 301-311. https://doi.org/10.1111/j.1365-2419.2009.00512.x.
  8. Kendall A and S Kim. 1989. Buoyancy of walleye pollock (Theragra chalcogramma) eggs in relation to water properties and movement in Shelikof Strait, Gulf of Alaska, Can J Fish Aquat Sci Spec Pub 108, 169-180.
  9. Kim S. 1987. Spawning behavior and early life history of walleye Pollock, Theragra chalcogramma, in Shelikof Strait, Gulf of Alaska, in relation to oceanographic factors. Ph. D. Dissertation, University of Washington, Seattle, U.S.A., 221.
  10. Kim S. 1990. Status of fishery and science of Bering Sea walleye pollock: (I) History and importance of fisheries. Ocean Res 12,117-128.
  11. Kim S and A Kendall. 1989. Distribution and transport walleye pollock larvae in Shelikof Strait, Gulf of Alaska, in relation to water movement. Rapp P-v Cons int Explor Mer 191, 127-136.
  12. Laurel BJ, LA Copeman, TP Hurst and CC Parrish. 2010. The ecological significance of lipid/fatty acid synthesis in developing eggs and newly hatched larvae of Pacific cod (Gadus microcephalus). Mar Biol 157, 1713-1724. https://doi.org/10.1007/s00227-010-1445-1.
  13. Lee JY, CS Lee, WK Kim, SU Park and BH Min. 2007. Effects of water temperature on egg developments, hatching and larval growth of the Pacific cod Gadus macrocephalus. J Aquaculture 20, 260-264.
  14. Li Z, J Yamamoto and Y Sakurai. 2015. Vertical position, specific gravity and swimming ability of Pacific cod Gadus macrocephalus yolk-sac larvae reared at four temperatures. Fish Sci 81, 883-889. https://doi.org/10.1007/s12562-015-0911-6.
  15. Miller B and Kendall AW. 2009. Early life history of marine fishes. University of California Press, Berkeley, U.S.A.
  16. Nishiyama, T, Hirano K and Haryu T. 1986, The early life history and feeding habits of larval walleye pollock Theragra chalcogramma (Pallas) in the southeast Bering Sea. INPFC Bull 45,177-277.
  17. Petereit C, Hinrichsen HH, Voss R, Kraus G, Freese M and Clemmesen C. 2009. The influence of different salinity conditions on egg buoyancy and development and yolk sac larval survival and morphometric traits of Baltic Sea sprat (Sprattus sprattus balticus Schneider). Sci Mar 73, 59-72. https://doi.org/10.3989/scimar.2009.73s1059.
  18. Saborido-Rey F, OS Kjesbu and A Thorsen. 2003. Buoyancy of Atlantic cod larvae in relation to developmental stage and maternal influences. J Plank Res 25, 291-307. https://doi.org/10.1093/plankt/25.3.291.
  19. Seo YS, Park ME, Kim JG and Lee U. 2007. Egg development and juvenile growth of the Pacific cod Gadus macrocephalus (Korean East Sea population). Korean J Fish Aquat Sci 40, 380-386. https://dio.org/10.5657/kfas.2007.40.6.380.
  20. Sundby S. 1997. Turbulence and ichthyoplankton: influence on vertical distributions and encounter rates. Sci Mar 61: 159-176.
  21. Woolley LD and JG Qin. 2013. Ontogeny of body density and the swimbladder in yellowtail kingfish Seriola lalandi larvae. J Fish Bio 82, 658-670. https://doi.org/10.1111/jfb.12020.